Diaphragm pump



March 30, 1954 J. w. DI'CKEY 2,673,522

DIAPHRAGM PUMP Filed April 10, 1951 3 Sheets-Sheet l IN V EN TOR.

ATTORNE Y WITNESS: 4 5

March 30, 1954 J. w. DICKEY 2,573,522

DIAPHRAGM PUMP Filed April 10, 1951 5 Sheets-Sheet 3 IN V EN TOR.

an 100% WITNESS: Y

Patented Mar. 30, 1954 DIAPHRAGM PUMP John W. Dickey, Newfield, N. dixAviation Corporation,

ware

Y., assignor to Bena corporation of Dela- Application April it, 1951,Serial No. 220,253

The present invention relates to a, diaphragm pump, and moreparticularly to such a pump in which the actuating mechanism isconnected to diaphragms through hydraulic transmission means.

In reciprocating pumps such as used for supplying fuel to internalcombustion engines, difficulty is sometimes encountered when pumpingliquids containing impurities such as dirt, metallic particles, wax,gum, etc. which tend to clog the reciprocating parts. It is commonpractice therefore, to provide filters, magnetic separators etc. toremove solid foreign material, and to form the reciprocatory parts withliberal clearances to nullify the efiect of deposits on the walls of thecylinder and piston, thus reducing to some extent the efiiciency of thepump.

It is an object of the present invention to provide a reciprocating pumpin which the reciprocating parts are sealed and protected from contactwith the liquid to be pumped.

It is another object to provide such a device incorporating flexiblediaphragms for propelling the liquid, said diaphragms being actuatedhydraulically so that the pressures on both sides of the diaphragms aresubstantially equal at all times, and the diaphragms are accordingly notsubjected to localized stresses, but serve merely as septums to separatethe liquid to be pumped from the liquid sealed in the pump.

It is another object to provide such a device in which a small amount ofair or other gas is sealed in the pump with the actuating liquid, so asto form a cushion and promote quiet and steady operation of the pump.

It is another object to provide such a device including a piston, aspring for projecting the piston, and an electromagnet for retractingthe piston and cooking the spring; which is so arranged that the springactuated stroke of the piston ejects a charge of liquid and draws in anew charge from the source of supply; while the cocking merely transfersa charge of liquid from one cavity in the pump to another, so that thisstroke can take place rapidly irrespective of the rate of consumption ofthe liquid by the device being supplied by the pump.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawing in which lis a vertical substantially mid-sectional View of a preferred embodimentof the invention, the electrical system thereof being showndiagrammatically;

from the pump stroke of the piston,

Claims. (Cl. 103-53) Fig. 2 is a section taken substantially on line 22in Fig. 1;

Fig. 3 is a view similar to Fig. 1 on a reduced scale showing anembodiment of the invention arranged for mounting within the supply tankof the liquid to be pumped;

Fig. 4. is a sectional detail of the electrical terminal structure shownin Fig. 3;

Fig. 5 is a side elevation of the pump shown in Fig. 3, illustrating themethod of assembly of the parts thereof; and

Fig. 6 is a top view of the same.

In Fig.1 of the drawing there is illustrated a substantially cylindricalcasing member i of magnetic material near the lower end of which isrigidly mounted a partition and pole piece member 2 which is also ofmagnetic material. An upper partition member 3 is rigidly mounted in thecasing 5 near the upper end thereof and a pump cylinder 6 ofnon-magnetic material is rigidly mounted at its ends within thepartition members 2 and 3, the various joints between the partitionmember, casing and pump cylinder being rendered fluid tight by suitablemeans such as by soldering.

A piston 5 of magnetic material is slidably mounted within the pumpcylinder :2 and is urged toward its upper position as illustrated bymeans of a, spring 6 bearing at its upper end against the end i of acounterbore 8 in the piston, and at its other end seating on aperforated bracket member s which is soldered as indicated at H to thelower end of the casing l. A cushioning spring i2 is seated in acounterbore the upper partition member 3 in order to prevent the pistonfrom hammering against the partition member when the pump is operatedwhile air bound.

Means for drawing the piston 5 downwardly so as to compress or cook thespring 6 is provided in the form of an electromagnet iii located in thecasing i surrounding the pump cylinder 4, with its lower end seatedagainst the lower partition and pole piece member 2, and its upper endin engagement with an upper pole piece member of magnetic material itwhich is rigidly mounted in the casing l in any suitable manner andclosely surrounds the pump cylinder 4.

An electrical system for actuating the electrocomprising a battery i?one terminal of which is grounded as indicated at i t, the otherterminal being connected through a manual switch is, insulated connector2i sealed in the case i, and conductor 22, to one terminal of theelectroinagnet it. The other terminal of it in. the upper end. of thepiston and bears against the element it of- 3 :the electromagnet isconnected by a lead 23 to a contact 24 which is arranged to cooperatewith a contact 25, grounded at 26, to open and close the circuit throughthe electromagnet.

The means for actuating the contacts 24, 25 which are here showndiagrammatically, is the same as that shown and described in the patentto Dickey et al. 2,472,067 issued June 7, 1949, so that it is believedto be unnecessar to further describe this feature since it forms no partof the present invention.

An inlet cap 21 is mounted on the lower end of the casing member I, thejoint therebetween being rendered fluid tight by a flexible septum 28which acts as a gasket to prevent leakage from the inlet chamber 29formed within the cap 2'l.

An outlet cap member 3| is similarly mounted on the upper end of thecasing member I, the joint therebetween being packed by the flexibleseptum and gasket member 32, the caps 21 and 3| being firmly held on theends of the casing member 2, by suitable means such as the tie bolts 30illustrated in Fig. 2.

The pump cylinder 4 and the spaces or chambers 33 and 34 in the ends ofthe casing l are filled with a suitable liquid which is confined by theflexible septums 28 and 32 so that the reciprocat ing movement of thepiston is transmitted hydraulically to said septums.

The inlet cap 21 is provided with a threaded socket 35 (Fig. 2) for thereception of an inlet conduit from a supply source: and means in theform of a manually adjustable needle valve 35 is provided for closingthe inlet when desired. The inlet opening 35 communicates with the inletchamber 29 through a communicating passage 31 which is controlled by acheck valve 38 arranged to admit fluid to the inlet chamber but preventreverse flow thereof. A conduit 39 connects the inlet chamber 29 to thepump outlet 4|, which latter is in communication with the chamber 42within the outlet cap 3|. A check valve 43 is located in the by-pass 39permitting passage of fluid from the inlet chamber to the outlet butpreventing backward flow thereof.

The inlet cap 21 is provided with a cup-shaped closure member 44 forminga sediment bowl which may be detached for removal of sediment or waterin the liqui to be pumped, and which is normally held in assembledrelation by suitable means such as a cap screw 45. A filter screen 46 isheld by a seat member 4! within the sediment bowl 44 in position tostrain out any solid matter suspended in the liquid to be pumped as itpasses from the inlet 35 toward the passage 3! into the inlet chamber29.

In order to quiet the operation of the pump and to form an hydraulicaccumulator for increasing the efiective capacity of the pump, anelastic diaphragm member 48 is arranged to form the upper wall of theoutlet chamber 42, and is enclosed by a dome-shaped element 49 formingan air chamber above the diaphragm 48 so as to cushion the action of thepump.

It has been found in use of pumps as here disclosed, that there is aslow drift of the liquid in the upper chamber 34 down into the lowerchamber 33 due to leakage past the piston 5 under the output pressure ofthe pump. This leakage gradually distend the lower diaphragm and tendsto impede the downward stroke of the piston and thus reduce theefficiency of the pump.

A preferred solution of this problem is to provide acheck-valve-controlled passage in the Dis 4 ton to allow the liquid toflow up through the piston during the downward travel.

In Fig. l of the drawing such an arrangement is shown in the form of atube having a press fit in an axial opening which traverses the solidportion of the piston 5, said tube being constricted at its lower end toform a seat against \svhich a ball valve 8! is pressed by a light sprinThis ball check valve does not interfere with the action of thediaphragm 28 in moving liquid up through the by-pass 39 on the downwardstroke of the piston since the pressure in the inlet chamber 29 is atthat time the same as in the outlet chamber 42, except for the slightamount necessary to raise the check valv 43. Consequently the pressurein the chambers 33 and 34. below and above the piston E aresubstantially equal, and there is no tendency to lift the ball check 8|except for the purpose of compensating for leakage past the piston 5 asabove set forth.

In operation, starting with the parts in the positions illustrated inFig. 1, closure of the manual switch 13 causes energization of theelectromagnet l5, which draws the piston 5 downward, thus cocking thespring 6 and causing the lower septum 28 to expel liquid from the inletchamber 29 past the check valve 43 and through the conduit 39 so as toenter the outlet chamber 42; such entry being permitted by the downwardmovement of the upper septum 32 which corresponds in direction andamount with the movement of the septum 2B. Deenergization of theelectromagnet 15 by the opening of the contacts 24, 25 in the usualmanner permits the spring 6 to move the piston 5 upward, dilating theseptum 32 and retracting the septum 28. The retraction of septum 28draws a fresh charge of liquid from the inlet 35 through the check valve38 into the inlet chamber 29, while the simultaneous dilation of theseptum 32 ejects a charge of liquid from the outlet 4! to the device tobe supplied by the pump. Since the downward stroke of the piston 5 asactuated by the electromagnet [55 merely serve to transfer the liquid tobe pumped from the inlet chamber 29 through the conduit 39 to the outletchamber 42, this stroke of the piston can always take place quickly sothat the electromagnet is only energized momentarily. The upward strokof the piston 5 under the action of the spring 6 is controlled by therate of consumption of the liquid by the device to be supplied. It willbe understood that the contacts 24, 25 are closed when the pistonreaches the end of its upward stroke, and are opened at the end of itsdownward stroke, as fully set forth in the Dickey et al. Patent2,472,067.

In Figs. 3 to 6 inclusive there i illustrated an embodiment of theinvention in which the pump is arranged to be mounted within the supplytank for the liquid to be pumped. The actuating parts of the pump itselfare the same as in the embodiment above described, and are similarlynumbered, but the inlet and outlet caps are modified for the intendedpurpose. The inlet cap 5! is here provided with a downwardly extendingthreaded socket 58 adapted to receive a conduit 59 terminating with afunnel-shaped fitting 6| holding a screen 52 located adjacent the bottomof the supply tank 63.

The outlet cap ll is provided with a mounting flange 12 arranged to beattached to the top of the supply tank 63, with the body of the pumpextending downwardly through an opening 13 in the supply tank, theflange being secured by suitable means such as cap screws 74 threadedinto a recnforcing ring 15.

The battery connection is here brought out through an insulatedconnector 76 traversing the mounting flange 12 as illustrated in Fig. 4.A grounding clip 77 is preferably provided for insuring electricalconnection of the pump with the body of the supply tank in order toinsure completion of the electrical circuit.

In some installations it is desirable to provide means for permitting aslight leakage of the discharged fluid back to the supply tank so as toprevent undesirable syphoning of the liquid and also to prevent thebuilding up of pressure within the supply caused by temperature changeswhen the system is idle. In the present system this is accomplishedsimply by drilling a small hole 78 in the conduit connecting the inletand outlet caps of the pump so that liquid may leak slowly back into thesupply tank.

In Fig. 3, the functions of the hydraulic accumulator diaphragm 48 ofFig. 1 are accomplished by trapping and sealing a suitable quantity ofair or other gas in the space 34 below the upper diaphragm 32 of thepump. The imprisoned gas 79 provides elasticity in the actuation of thediaphragm 32 so as to quiet the operation of the pump and smooth out theflow of the liquid being pumped.

The operation of this embodiment of the pump is the same as theembodiment first described, and further description thereof is,therefore, deemed unnecessary.

Although but two embodiments of the invention have been shown anddescribed in detail, it will be understood other embodiments arepossible and that various changes may be made in the design andarrangement of the parts without departing from the spirit of theinvention.

I claim:

1. In a pump a cylindrical casing, a partition rigidly mounted near eachend of the casing, a pump cylinder mounted at its ends in saidpartitions coaxially with the casing, means for sealing the pumpcylinder in the partitions and the partitions in the casing, a piston inthe pump cylinder, means for reciprocating the piston; inlet and outletcaps fixed to the ends of the easing, flexible septums closing the endsof the casing and packing the joints between the easing and caps, a,conduit conducting liquid from the inlet cap to the outlet cap, and apair of check valves preventing back-flow of liquid through the inletchamber and conduit.

2. A pump as set forth in claim 1 in which the piston is provided withan axial passage therethrough, and including further a check valvelocated in said passage and preventing backward flow of fluid throughthe passage when ferring conduit to the outlet cap.

4. A pump as set forth in claim 3 in which the outlet cap is providedwith a flange and means 5. In a pump a casing, means including a pair ofseptums forming an inlet chamber and an outlet chamber oppositelylocated in the casing, a cylinder fixedly mounted in the casingintermediate said chambers, a piston slidably mounted in the cylinder,means for reciprocating the piston, said cylinder being filled withfluid confined by said septums, which fluid transmits the motion of thepiston to the septums, a conduit connecting the inlet chamber to theoutlet chamher and a pair of check-valves controlling the passage offluid through the inlet chamber and conduit; the means for reciprocatingthe piston comprising a spring which moves the piston in a direction tocause liquid to be drawn into the inlet chamber and simultaneouslydischarged from the outlet chamber, and an electromagnet oppositedirection, cocking the spring and causing the transfer of liquid fromthe inlet chamber to the outlet chamber.

JOHN W. DICKEY.

References Cited in the file of this patent UNITED STATES PATENTS

